1. Field of the Invention
The present invention generally relates to well completion. More particularly, the present invention relates to methods for expanding an expandable sand screen. More particularly still, the present invention includes trip saving methods for use with an expandable sand screen.
2. Description of the Related Art
The completion of wells includes the formation of a borehole to access areas of the earth adjacent underground formations. Thereafter, the borehole may be lined with steel pipe to form a wellbore and to facilitate the isolation of a portion of the wellbore with packers. The casing is perforated adjacent the area of the formation to be accessed to permit production fluids to enter the wellbore for recovery at the surface of the well. Whether the well is drilled to produce hydrocarbons, water, or geothermal energy, or is intended as a conduit to stimulate other wells, the basic construction is substantially the same.
In order to eliminate or reduce the production of formation sand, a sand screen is typically placed adjacent to the perforations or adjacent to an open wellbore face through which fluids are produced. A packer is usually set above the sand screen and the annulus between the screen and the casing is then packed with a relatively course sand, commonly referred to as gravel, to form a gravel pack around the sand screen for filtering sand out of the in-flowing formation fluids. In open hole gravel pack installations, the gravel pack also supports the surrounding unconsolidated formation and helps to prevent the migration of sand with produced formation fluids.
Recently, technology has arisen making it possible to expand a tubular in a wellbore. These in-situ expansion apparatus and methods permit a tubular of a smaller diameter to be inserted into a wellbore and then expanded to a larger diameter once in place. The advantages of time and space are obvious.
The in-situ expansion technique has been applied to sand screens, or those tubular members at the lower end of production tubing designed to permit the passage of production fluid therethrough but to inhibit the passage of particulate matter, like sand. An exemplary sand screen that can be expanded in the wellbore is described in U.S. Pat. No. 5,901,789 which is incorporated by reference herein in its entirety. Generally, an expandable sand screen xe2x80x9cESSxe2x80x9d consists of a perforated base pipe, woven filtering material and a protective, perforated outer shroud. Both the base pipe and the outer shroud are expandable and the woven filter is typically arranged over the base pipe in sheets that partially cover one another and slide across one another as the ESS is expanded.
In one method of in-situ expansion, a wedge-shaped cone member is inserted into the well adjacent an end of the expandable screen with the tapered surface of the cone decreasing in diameter in the direction of expansion. The cone typically is mounted on a separate string to permit it to move axially in the wellbore independent of the expandable screen. When the screen is adjacent the area where production fluid will enter the perforated casing, the cone is urged along the inner bore of the expandable screen, thereby expanding the screen""s inner bore to the size of the outer diameter of the cone.
In another method of expansion, an expansion tool is run into the wellbore on a string of tubulars to a location within the expandable screen to be expanded. The expansion tool includes radially expandable roller members, which can be actuated against the wall of the screen via fluid pressure. In this manner, the wall of the screen can be expanded past its elastic limits.
One benefit from using the expandable sand screen is that, once expanded, the annular area between the screen and the wellbore or casing is mostly eliminated. Thus, the gravel pack may no longer be necessary. Further, in an open hole, the ESS may be expanded to a point where its outer wall places a stress on the wall of the wellbore, thereby providing support to the walls of the wellbore to prevent dislocation of particles.
On the other hand, problems exist with the present methods of expansion. For example, when a cone is used, the ESS has a tendency to xe2x80x9crelaxxe2x80x9d after expansion. As a result, the ESS will form a loose fit with the casing or the wellbore. In many simple applications, the use of the more costly and complex roller based expansion method is not necessary. Further, both expansion methods rely on heavy and stiff expansion tubular strings which are not always readily available at job locations.
There is a need therefore for an apparatus and method to expand an expandable sand screen in order to form a tight fit between the screen and the wellbore or casing. There is yet a further need for an apparatus and method for expanding an expandable sand screen in a single trip.
The present invention provides apparatus and methods for expanding an expandable tubular in the wellbore. In one aspect, the expandable tubular is expanded using one or more packers. The one or more packers may include an inflatable packer or a mechanical packer. In another aspect still, the expandable tubular is an expandable sand screen.
In one embodiment, an apparatus including a section of expandable sand screen and an inflatable packer is disposed in the wellbore on coil tubing. Thereafter, the inflatable packer in actuated to expand the expandable sand screen adjacent to a producing area of the wellbore. In another embodiment, the expandable sand screen includes one or more sealing means disposed on the ends of the expandable sand screen to isolate the producing area. The expansion of the expandable sand screen will also expand the one ore more sealing means.